package cn.tedu.sp06.fb;

import cn.tedu.web.util.JsonResult;
import org.springframework.cloud.netflix.zuul.filters.route.FallbackProvider;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.client.ClientHttpResponse;
import org.springframework.stereotype.Component;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;

/**
 * 调用商品失败时，执行这里的降级代码，返回降级结果
 */@Component
public class ItemFB implements FallbackProvider {
    /**
     * 针对哪个后台服务调用失败，应用当前降级类
     * 返回值："item-service" 只针对商品服务降级
     *        "*"            对所有后台服务都应用当前降级类
     *        null           对所有后台服务都应用当前降级类
     */
    @Override
    public String getRoute() {
        return "item-service";
    }

    /**
     * 返回给客户端的降级响应数据
     * 封装到response 对象
     *
     *
     */
    @Override
    public ClientHttpResponse fallbackResponse(String route, Throwable cause) {
        return new ClientHttpResponse() {
            @Override
            public HttpStatus getStatusCode() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR;
            }

            @Override
            public int getRawStatusCode() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR.value();
            }

            @Override
            public String getStatusText() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR.getReasonPhrase();
            }

            @Override
            public void close() {
//            用来关闭下面的流
//                BAIS内存数组流，不占用底层系统资源，不需要关闭
//                需要关闭的流：
//                文件流，占用系统文件资源
//                网络流，占用网络资源
//                数据库流，占用数据库资源
            }

            @Override
            public InputStream getBody() throws IOException {
//                JsonResult -->{code:500,msg:调用后台服务出错，data:null}
                String json = JsonResult
                        .err()
                        .code(500)
                        .msg("调用后台服务出错")
                        .toString();
//                将json 封装到BAIS
                return new ByteArrayInputStream(json.getBytes("UTF-8"));
            }

            @Override
            public HttpHeaders getHeaders() {
//                Content-Type: application/json;charset=UTF-8
                HttpHeaders h = new HttpHeaders();
                h.set("Content-Type","application/json;charset=UTF-8");
                return h;
            }
        };
    }
}
